Unravelling the convoluted nomenclature of Marphysa simplex (Annelida, Eunicidae) with the proposal of a new name and the re-description of species Author Molina-Acevedo, Isabel Cristina https://orcid.org/0000-0001-5487-895X Estructura y Funcion del Bentos, Depto. Sistematica y Ecologia Acuatica, El Colegio de la Frontera Sur, Chetumal, Quintana Roo, Mexico & South China Sea Repository and Reference Centre, Institute of Oceanography and Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia imolina@ecosur.edu.mx Author Idris, Izwandy https://orcid.org/0000-0003-1516-8175 South China Sea Repository and Reference Centre, Institute of Oceanography and Environment, Universiti Malaysia Terengganu, 21030 Kuala Nerus, Terengganu, Malaysia text Zoosystematics and Evolution 2021 2021-02-10 97 1 121 139 http://dx.doi.org/10.3897/zse.97.59559 journal article http://dx.doi.org/10.3897/zse.97.59559 1860-0743-1-121 94AF3450CEAF4F0C8149C3F9BA9E405A D6B72C47EAF45F7A94A24A00BAFAF95B Marphysa fijiensis nom. nov. Figures 1 , 2 , 3 , 4 , Table 1 Marphysa simplex Treadwell, 1922: 151-152, pl. 5, figs 8-12, text-figs 39 ( non Crossland, 1903); - Hartman 1956 : 254, 262, 268, 286. Material examined. Holotype. Fiji · Suva Harbour; Apr-Jun, 1920; AMNH 1920-1530. Comparative material examined. Eunice mossambica Peters, 1854 Mozambique · one specimen and vial with six parapodia; lectotype ZMB 4005 · 3 adult specimens, same data as for the lectotype; paralectotypes ZMB 47 · one specimen; same data as for the lectotype; ZMB F2046 · seven adult specimens; same data as for the lectotype; ZMB 4005. Marphysa moribidii Idris, Hutchings & Arshad, 2014 Malaysia · two adult specimens; Pantai Kelanang, Morib, Selangor; 2°45'39.85"N , 101°26'08"E ; in mangrove vegetation; 19 Jul 2011; I. Idris leg.; paratype AM W.38690. Nauphanta novaehollandiae Kinberg, 1865 Australia · one specimen divided into four vials, one of them with maxillary apparatus; Sydney Port Jackson; 33°54'S , 151°11'E ; Eugenie Epx. 1851-53; holotype SMNH-type-432. Etymology. The new name denotes the geographic region where the specimen was collected. Description. Holotype complete (Fig. 1A-F ), ventrally dissected (Fig. 1C ), with 198 chaetigers, L10 = 8.2 mm, W10 = 2.5 mm, TL = 93 mm. Anterior region with dorsum convex, flat ventre, body depressed from chaetiger 6 (Fig. 1D ), widest at chaetiger 17, tapering after chaetiger 41. Figure 1. Marphysa fijiensis nom. nov., holotype (AMNH 1920-1530). A, B. Anterior end, dorsal view; C. Anterior end, ventral view; D. Anterior end, lateral view; E. Median region, lateral and ventral views; F. Pygidium, lateral view. Scale bars: 0.35 mm ( A ); 2 mm ( B-D ); 0.5 mm ( E, F ). Prostomium bilobed, 1.3 mm long, 1.6 mm wide; lobes frontally rounded; median sulcus shallow and deep ventrally (Fig. 1A, B ). Prostomial appendages in semicircle, median antenna isolated by a gap. Palps reaching second peristomial ring; lateral antennae reaching first chaetiger; median antenna reaching second chaetiger. Palpophores and ceratophores ring-shaped, short, slender; palpostyles and ceratostyles tapering, thick. Eyes absent. Peristomium (1.7 mm long, 2.3 mm wide) larger than prostomium, first ring twice as long as second ring, separation between rings distinct on all sides (Fig. 1A-C ). Ventral lip dissected, with several shallow wrinkles (Fig. 1C ). Maxillary apparatus lost, according to Treadwell with MF = 1+1, 5+5-6, 9+0 2+8, 1+1. Branchiae pectinate with up to five long filaments, from chaetigers 22 to 184L-195R (Figs 1E , 2D, E ). Six first branchiae with one filament; reaching maximum five filaments in chaetigers 79L-178L; last 12 branchiae with one filament (Fig. 3A ). Branchial filaments longer than dorsal cirri, except in first six and last 10 branchiae. Figure 2. Marphysa fijiensis nom. nov., holotype (AMNH 1920-1530). A. Chaetiger 3; B. Chaetiger 8; C. Chaetiger 14; D. Chaetiger 123; E. Chaetiger 188. Marphysa mossambica (Peters, 1854), lectotype (ZMB 4005a). F. Chaetiger 3; G. Chaetiger 8; H. Chaetiger 15; I. Chaetiger 293; J. Chaetiger 398. All chaetigers in anterior view. The colours in drawings indicate the prechaetal (light brown), chaetal (light yellow) and postchaetal (light green) lobes. Scale bars: 0.1 mm ( A-E ); 0.2 mm ( F-J ). Figure 3. Distribution of branchial filaments throughout the body. A. Holotype of Marphysa fijiensis nom. nov. (AMNH 1920-1530) with L10: 8.2 mm, TL: 93 mm and 198 chaetigers; B. Paralectotype of Marphysa mossambica (Peters, 1854) (ZMB 47) with L10: 10.3 mm, TL: 290 mm and 429 chaetigers. First two parapodia smaller; best developed in chaetigers 4-21, following parapodia gradually decreasing in size. Dorsal cirri conical in all chaetigers; longer than ventral cirri in anterior and posterior chaetigers, of similar size in median chaetigers; best developed in chaetigers 3-30, gradually decreasing posteriorly (Fig. 2A-E ). Prechaetal lobes short, as transverse folds in first three chaetigers, following lobes with upper edge longer than lower; transverse folds in most posterior chaetigers (Fig. 2A-E ). Chaetal lobes rounded in most chaetigers, shorter than postchaetal lobe, with aciculae emerging dorsal to mid-line; from chaetiger 33, longer than other lobes, aciculae emerging in mid-line (Fig. 2A-E ). Postchaetal lobes slightly developed in first 55 chaetigers; ovoid in first two chaetigers, rounded in the following ones, progressively smaller from chaetiger 14; from chaetiger 56 inconspicuous (Fig. 2A-E ). Ventral cirri digitiform in first 13 chaetigers; in chaetigers 14 to 126 with rounded, poorly developed swollen base and digitiform tip; conical from chaetiger 127, gradually decreasing in size posteriorly (Fig. 2A-E ). Aciculae blunt, basally reddish and translucent distally; colourless in posterior chaetigers (Fig. 2A-E ). First two chaetigers with two aciculae; in chaetigers 3-10 with three or four aciculae; in chaetigers 11-24 with four aciculae; in chaetigers 25-43 with three aciculae; in chaetigers 44-85 with two aciculae; from 86 with only one acicula. In median-posterior region, aciculae twice as wide as subacicular hook (Fig. 4F, G ). Figure 4. Marphysa fijiensis nom. nov., holotype (AMNH 1920-1530). A. Limbate chaetae, chaetiger 8; B. Limbate chaetae, chaetiger 188; C. Thick isodont narrow, with short and slender teeth, chaetiger 3; D. Thick isodont wide with short and slender teeth, chaetiger 152; E. Thick isodont wide with short and slender teeth, chaetiger 188; F. Unidentate subacicular hook, chaetiger 123; Bidentate subacicular hook, chaetiger 152. Arrows in F: upper one indicates the acicula; lower one indicates the hood of the subacicular hook. Scale bars: 40 μm ( A, B, F, G ); 12.5 μm ( C-E ). Limbate chaetae in supra- and subacicular positions. Limbate supracicular chaetae reduced in number around chaetiger 16, chaetae of two lengths in same chaetiger, with longer blades in dorsal position and with short blades in ventral position. Limbate subacicular of two lengths, with short blades in dorsal position and with longer blades in ventral position (Fig. 4A, B ). Two types of pectinate chaetae; in all chaetigers, 2-3 thick isodont narrow chaetae, with up to 16-18 teeth short and slender teeth (Fig. 4C ); in median-posterior chaetigers, 4-5 thick isodont wide chaetae, with up to 38-42 teeth short and slender teeth (Fig. 4D, E ); anodont pectinate chaetae not observed. Compound chaetae absent. Subacicular hooks starting from chaetigers 38R-39L, one per chaetiger, with discontinuous distribution, in last 25 chaetigers, the hooks are absent; unidentate in median region with one hood (possibly with second hood broken) (Fig. 4F ); bidentate in median-posterior region, translucent, with blunt teeth, distal tooth directed upwards, proximal tooth larger, directed laterally (Fig. 4G ). Pygidium with two pairs of anal cirri broken (Fig. 1F ). Distribution. Known only from the type locality. Habitat. Uncertain. Possibly coral reefs or mudflats ( Treadwell 1922 ). Remarks. The first comment on the synonymy of Marphysa fijiensis nom. nov. (as M. simplex Treadwell, 1922) and M. mossambica was made by Hartman (1956) . Subsequently, Glasby and Hutchings (2010) supported this idea, stating that the morphology described by Treadwell was very similar to the smaller-sized specimens of M. mossambica . However, after a detailed morphological comparison of both species' type material, we found marked differences. Marphysa fijiensis nom. nov. lacks eyes, whereas they are present in M. mossambica . Additionally, M. fijiensis nom. nov. (L10: 8.2 mm) has a maximum number of five branchial filaments in the median region (Fig. 3 ), whereas M. mossambica (L10:8.5-11.5 mm), has a maximum number of eight branchial filaments in the mid-posterior region (Fig. 3 ). In M. fijiensis nom. nov., the chaetal lobe is rounded in the anterior region and the postchaetal lobe is oval in the first three chaetigers. In contrast, in M. mossambica , the chaetal lobe is rectangular in the anterior region and the postchaetal lobe is digitiform in the first three chaetigers. Likewise, M. fijiensis nom. nov. has the subacicular hook present from chaetiger 25, contrasting to chaetigers 35-65 in M. mossambica . Marphysa fijiensis nom. nov. resembles M. moribidii Idris, Hutchings & Arshad, 2014 and M. novaehollandiae (Kinberg, 1865) in lacking compound chaetae. However, M. fijiensis nom. nov. lacks the peduncle in prostomial appendages, with swollen base in ventral cirri starting from chaetiger 14 and the acicula is twice as wide as the subacicular hook in the median-posterior region. In contrast, M. moribidii (L10: 12.2-20 mm) has a peduncle at the base of the palpo- and ceratostyles, bears ventral cirri with a swollen base starting from chaetiger 6 and has a subacicular hook similar in width to the acicula throughout the body. Furthermore, M. fijiensis nom. nov. has the prechaetal lobe as a transverse fold throughout the body, the chaetal lobe rounded throughout the body, the ventral cirri with a swollen base starting from chaetiger 14 and the subacicular hook starting from chaetiger 25; while M. novaehollandiae (L10: 6.6-9.6 mm) has the prechaetal lobe with dorsal edge longer than the ventral side in the first chaetigers, the chaetal lobe rectangular in the anterior region, the ventral cirri with a swollen base starting from chaetiger 8 and the subacicular hook starting from chaetigers 39-42. The comparison of M. fijiensis nom. nov. with related species is provided in Table 1 . Table 1. Morphological features of Marphysa group A sensu Fauchald (1970) . Abbreviations: MF: Maxillary formula, roman numerals refer to number of maxilla; MxC: maxillary carriers; CIS: closing system; COp: cavity opening; PR-I: first peristomial ring; PR-II: second peristomial ring; Chaet: chaetiger; p/a: present/absent; AR: anterior region; MR: median region; PR: posterior region; SH: subacicular hook. INSS: Isodont narrow with short and slender teeth; INLS: Isodont narrow with long and slender teeth; IWSS: Isodont wide with short and slender teeth; IWLS: Isodont wide with long and slender teeth; AWLT: Anodont wide with long and thick teeth.

Morphological feature	M. moribidii Idris et al., 2014	M. mossambica (Peters, 1854)	M. novaehollandiae (Kinberg, 1865)	M. fijiensis nom. nov.
Source of information	paratypes AM W. 38690; additional material	lectotype ZMB 4005a; paralectotypes ZMB 47; ZMB F2046, ZMB 4005	holotype SMNH-type-432; AM W.33021	holotype AMNH 1920-1530
Size (mm): L10, W10	12.2-20, 6.3-8.2	8-11.5, 3.6-8.1	6.6-9.6, 4-4.2	8.2, 2.5
Prostomium: shape	bilobed	bilobed	bilobed	bilobed
Palps: reaching	PR-II	PR-II or Chaet 1	PR-II	PR-II
Lateral antennae: reaching	PR-II or Chaet 1	middle Chaet 1 or 2	middle Chaet 1	Chaet 1
Median antennae: reaching	Chaet 1 or 2	Chaet 2 or 3	middle Chaet 2	Chaet 2
Peduncle in prostomial appendages	present	absent	absent	absent
Eyes	absent	present	present	absent
MF: MII, MIII, MIV	5-6+4-6, 7-8, 6+8-10	5+5-6, 6-7, 3-4+8-9	4-5+6, 7, 5+8-9	5+5-6, 9, 2+8
MI vs. MxC: proportion	2.4-2.8 x longer than MxC	2-3 x longer than MxC	2.4-3.2 x longer than MxC	?
MI vs. CIS: proportion	4.3-5.7 x longer than CIS	5-7 x longer than CIS	4.4-8 x longer than CIS	?
MII vs. COp: proportion	4.3-4.7 x longer than COp	3.2-4 x longer than COp	4.5-5.3 x longer than COp	?
Branchiae: shaped	pectinate	pectinate	pectinate	pectinate
Branchiae: start chaetiger; last chaetiger before pygidium	27-39; 15-37	23-48; 29-126	21-25; 15	22; 3
Branchial filaments: numbers; length of the filaments	7-10; long	7-8; long	6-7; long	5; long
Dorsal cirri: shaped	conical	conical with wide base	conical	conical
Prechaetal lobe: shaped	transverse fold	AR: upper edge longer than lower, MR, PR: transverse fold	AR, MR: upper edge longer than lower, PR: transverse fold	AR, MR: upper edge longer than lower, PR: transverse fold
Chaetal lobe: shaped	rounded	AR: rectangular MR, PR: rounded	AR, MR: rectangular, PR: rounded	rounded
Developed postchaetal lobe: end chaetiger	50-96	27-70	32-38	55
Postchaetal lobe: shape in body regions	Chaet 4: digitiform short, Chaet 4-10, 10: rounded	Chaet 4: digitiform short, Chaet 4-10, 10: rounded	Chaet 4: ovoid, Chaet 4-10, 10: rounded	Chaet 4: ovoid, Chaet 4-10, 10: rounded
Ventral cirri in first chaetigers: shape	digitiform	digitiform	digitiform	digitiform
Ventral cirri with swollen base: start chaetiger; last chaetiger before pygidium	6; 62-96	7-9; 96-208	8; 41	14; 72
Ventral cirri in most posterior chaetigers: shape	conical	conical	conical	conical
Aciculae: shape; colour	blunt, dark	blunt, dark	blunt, dark	blunt, dark
Subacicular limbate chaetae: (p/a); distribution	present; all chaet	present; all chaet	present; all chaet	present; all chaet
Pectinate chaetae: type in AR; MR, PR	INLS; IWSS, IWLS, AWLT	INLS; IWSS, IWLS, AWLT	INLS; IWSS, IWLS,?	INSS; IWSS
Pectinate chaetae: number per type	1-2; 3-4, 1-2, 1-2	1-2; 2-3, 2-3, 1-2	1-2; 1-2, 3-4;?	2-3; 4-5
Pectinate chaetae teeth: number per type	18; 52, 26, 7	18-19; 56, 27, 9-10	25; 50-51, 35;?	16-18; 38-42
Subacicular hook: start chaetiger	56-65	35-65	39-42	38
Subacicular hook: shape; colour	bidentate, translucent	bidentate, translucent	bidentate, translucent	MR: unidentate, PR: bidentate, translucent
Width acicula vs. SH in MR-PR: proportion	similar width	Acicula 2 x wider than SH	Acicula 2 x wider than SH	Acicula 2 x wider than SH
Subacicular hook: distribution	discontinuous	discontinuous	discontinuous	discontinuous